In the following the invention will be described by referring to a specific field, namely the pulp industry, where the problem which the invention is intended to solve is well-known, which is not, however, to be seen as having any limiting effect on the scope of the invention, which is defined by the subsequent patent claims. In the pulp industry the fibre suspension is often treated with gas, for example with the intention of bleaching the pulp. Subsequently it is desirable to separate the residues of the added treatment gas from the pulp before the latter is subjected to further treatment. Recently it has become much more common to use ozone in connection with bleaching the pulp. Ozone is produced using air or oxygen. After ozone bleaching the major part of the air or oxygen remains as a residual gas. This residual gas also contains small quantities of ozone. The residual ozone remaining after the treatment of the pulp cannot, for environmental reasons, be released directly into the atmosphere but must first be neutralised, which most frequently is achieved in a so-called "ozone destroyer".
However, in order that it should function properly an "ozone destroyer" requires a very high degree of purity in the gas that is to be treated. This implies that the gas which is separated from the pulp suspension must be purified from residual fibres and any other impurities, such as sulphur dioxide (SO.sub.2), sulphuric acid (H.sub.2 SO.sub.4), etc., before it is introduced into an "ozone destroyer".
One purpose of the invention is thus to present a process and a device for the separation of residual fibre, etc., from an above-mentioned gas stream.
A further purpose of the present invention is to present a process and a device for the separation of gas from a fibre suspension comprising a cleaning device which requires relatively little maintenance and which preferably can be run continuously.